1. Field of the invention:
This invention relates to a process for manufacturing metallurgical carbonaceous materials from coals, and more particularly, a process for manufacturing carbonaceous materials from coals of a low rank of coalification.
2. Description of the prior art:
Heretofore, it has been a common practice to subject low-grade coals to a hydrogenation reaction, so as to convert the same into various kinds of high-grade carbonaceous materials, which may be used as liquid or solid fuel at room temperature, or which may be used for other purposes. There is known, for instance, a process for hydrogenating coals of a low rank of coalification and a high oxygen content, such as subbituminous coal, brown coal, lig-nite and peat, in which coals are subjected to a reduction reaction at high temperature and pressure (300.degree. to 450.degree. C, 50 to 150 atms.) in a mixture gas containing carbon monoxide, steam, and, if desired, hydrogen in the presence of a carbon monoxide base solvent, thereby converting the coals into high-grade carbonaceous materials. (Page 220, No. 3, Volume 12, H. R. Appell & I. Wender: Preprints Symp. Natl. Meeting, Am. Chem. Soc. Div. Fuel Chem.). Carbonaceous materials derived according to the prior art process above described pose no problem when used as fuel. However, these materials are found to be unsuited for use as metallurgical carbonaceous materials for final products, particularly, such as iron making cokes, because of their relatively lower strength. The study by the inventors reveal that the aforesaid shortcomings in carbonaceous materials derived according to the prior art process stem from their high oxygen and hydrogen contents, i.e., a content ratio (in atom) of oxygen-to-carbon of not less than 0.04, and a content ratio (in atom) of hydrogen-to-carbon of not less than 1.0. In this respect, it was also found that for use as metallurgical carbonaceous materials, the content ratio of oxygen-to-carbon should be not more than 0.05, preferably not more than 0.04, and the content ratio of hydrogen-to-carbon should range from 0.5 to 1.0, preferably from 0.6 to 0.8.